Solid Foundations for Scaffold Safety
By Jordan Hollingsworth, MS, ASP, CHST, CHSP, CRIS®
Safety Advisor, Design and Construction
They’re one of these most common features on construction sites and in industrial settings — and one of the most inherently dangerous. Workers take them for granted, failing to give them a second thought. They reach to impressive heights, but far too little attention is paid to their connections to the ground. While they may be ordinary and utilitarian, they tend to fail in dramatic, newsworthy ways.
They are the platforms and climbing devices we describe as scaffolding. Although they may not get the attention they deserve from the workers who use them, the people who are responsible for those workers’ safety recognize the danger. That’s important, because nearly 4,500 workers are injured each year in scaffold-related incidents. As many as 50 workers actually die. No wonder OSHA puts such a strong focus on scaffold safety, with their inspectors making scaffold flaws one of their most-cited violations.
“Scaffolding” is a broad term that covers many different types of platforms and systems. Because the most common on construction sites and in manufacturing applications is the fabricated modular frame type that can be assembled into a variety of configurations for different heights and tasks, this article will focus on that type. However, most of the concepts and counsel incorporated here also applies to other types.
Training: the critical first step
It isn’t that scaffolds are any more or less inherently dangerous than other aspects of worksites. Safety issues surrounding scaffolds tend to be the result of a lack of awareness of the hazards they present, along with a lack of familiarity with the procedures that will minimize risk. Knowing both the potential hazards and the steps that can be taken to minimize those hazards will eliminate much of the potential for problems and injuries.
That’s why proper training is critically important for every worker who erects, inspects, maintains, or uses scaffolding on a worksite. Note that the list includes workers who “use” scaffolding. That includes workers who perform their tasks on or from the scaffold, as well as those who use scaffolding as a means to get to their own worksites. Simply put, nobody should be able to set foot on any part of a scaffold without proper training.
Some workers will react to that concept with surprise, or even contempt. “All I do is stand on the scaffold,” they’ll say. “Why do I need to be trained for that?”
One reason is that OSHA demands it. But the more important reason is to ensure their safety. They need to be made aware of correct use of the scaffold and how to handle materials and tools when working on it. Workers should be familiar with load ratings, and how those ratings might affect a particular task (such as whether the scaffold will safely accommodate a heavy piece of equipment along with their own weight). They need to be cognizant of fall-protection requirements and other safety features such as toe boards. They should be taught to look around to identify adjacent hazards, such as moving equipment, electrical wires, or hot pipes. Most of all, they need to understand the standard tagging system for scaffolds.
The other type of training is referred to as Competent Person training. Under safety regulations, a competent person is responsible for overseeing and coordinating all aspects of scaffolding. Those responsibilities include ensuring that they are erected, moved, dismantled, and maintained properly, and that all workers who perform tasks on the scaffold fully understand the correct safety procedures. For example, the competent person has to decide whether the workers who are assembling or dismantling the scaffold will need fall protection while performing those tasks.
Training should be updated whenever substantial changes are made to the scaffold’s structure or to the tasks that are being performed.
Read and follow all directions
Scaffolds seem to be fairly simple structures, and it’s not unusual for workers to start slapping them together without any extra thought, assuming that all systems and applications are exactly the same. That isn’t the case.
Each scaffolding system is engineered differently. Interchanging components from other systems or manufacturers may look safe, but it also may compromise the scaffold’s structural integrity. That can lead to anything from a slightly unstable work surface to an actual collapse. Unless the manufacturer specifically indicates that the components are compatible and can work together, don’t mix them.
A rule of thumb is that scaffolds will become unstable once the overall height reaches four times the length of the shortest part of the base. However, that rule applies only when the scaffold has been properly assembled, has been set on the correct base, and is in plumb. Going beyond that limit – even for a task that takes just a few minutes – is inviting trouble. Additionally, extreme weather conditions may rule out the use of an otherwise safe scaffold.
Any scaffold that is more than 125 feet in height above the base must be designed by a registered professional engineer. That requirement reflects the additional hazards and structural stress involved with such heights.
Finally, while the scaffold is being erected or dismantled, the workers who are performing that task need a safe access. Typically, that is either a stair tower or a bolt-on ladder. Workers who are accustomed to scrambling up the side braces during assembly are often surprised by (and resistant to) that requirement.
Create a firm foundation
Even the most carefully engineered and assembled scaffold will be unsafe if it doesn’t have a firm foundation. It’s common for workers to believe that simply adjusting the legs to the right height will prevent problems from occurring, but the bigger issue is what is supporting those legs.
Scaffolds must always be set on a firm foundation, so if the surface below the legs doesn’t offer sufficient strength to withstand the weight and stress, steps must be taken to compensate. Depending on the specific condition of the surface, that may include the use of mud sills or base plates. Any bracing must be properly secured to ensure that it will not become loose once under stress.
One way to enhance the safety of scaffolds is to consider the need for scaffolding when staging construction projects. With many projects, outdoor features such as sidewalks, driveways, and parking areas are often the last items to be constructed, because the architects and construction managers want to limit potential damage.
However, pouring sidewalks, slabs, and other elements early in the project means that you’ll have solid, level surfaces for scaffolds. Any minor damage to those surfaces that is caused by the scaffolds is easy to repair, and the cost of those repairs is usually clearly offset by the time and trouble saved when erecting scaffolds — not to mention the substantially lower risk of injury resulting from a collapse.
If the scaffold needs to be tied into the structure, proper procedures must be followed. Simply tying the scaffold in place with wire may be an accepted practice among workers, but it violates OSHA regulations.
Check the hazards at the beginning of every shift
Construction sites are places of constant change. A scaffold that was safe a month ago may have become unsafe because of something that was constructed nearby, or because of a task that is now being performed in an adjacent area. That is why hazard analysis needs to be an ongoing process. In addition, scaffolding hazards vary with the nature of the tasks being performed and the operating environment.
Typically, the biggest hazard is falls, which explains the rationale for requiring guardrails or some type of fall-protection equipment on scaffolds that are at least ten feet above the ground or next level.
Because most scaffolds are constructed from metal components, contact with live power lines may create an electrocution hazard. That’s especially true when workers are using metal strapping or tools in close proximity to the lines. Overhead equipment poses a hazard for head injuries.
Access to and from the scaffold can create its own set of hazards, because the potential for slips and falls increases as workers ascend or descend from the scaffold. If the elevation difference between a scaffold and an adjacent surface is greater than 24 inches, a ladder or a step must be used. This requirement is frequently neglected on movable scaffolding. OSHA rules prohibit using the scaffold’s bracing as a point of access or ascent. If the scaffold includes stair-type ladders, they should include handrails, rest platforms, and treads to reduce the possibility of slipping. Hook-on or attachable ladders must be designed specifically for the scaffold and positioned so that they do not cause it to tip.
Finally, weather conditions can create or contribute to hazards. A platform that becomes wet or icy creates a risk for skips and falls. Icicles that form on portions of the structure above the scaffold may thaw and suddenly drop on workers.
Use and document a tagging system
The most common way to inform workers about the safety of a scaffold is to use color-coded tags. At the beginning of each shift, a competent person inspects the scaffold and attaches one of three tags. A green tag signifies that the scaffold has been inspected and is safe for use.
A yellow tag sends the message that the workers can use the scaffold only under certain conditions. As an example, a yellow tag may mean that the workers need to be aware of a specific trip hazard, or may need to use fall protection. A red tag makes it clear that nobody can occupy the scaffold because it’s not ready for use, or because there’s a problem with it (or the environment).
Placing the tag is only part of the process. In OSHA’s eyes, if you fail to document that you performed the inspection and placed the tag, that never took place. Besides meeting the legal requirements, having clear documentation will also help you deal with the insurance company if an incident occurs.
Inspect and inspect again
Scaffolds must be inspected at least once a day by a competent person. If the structure of the scaffold or its surrounding area have been altered, or if weather conditions change, it should be re-inspected.
When performing those inspections, focus on the tasks that will be performed that day, and verify that the scaffold will provide a safe platform. The inspection should include the work platform itself, as well as the integrity of the entire structure.
If the work environment involves multiple shifts, a competent person should conduct his or her own inspection for the benefit of the workers on that shift. If he or she notices a yellow or red tag from the previous shift, that person should determine whether the tag is still needed.
Above all: respect scaffolding
We tend to think of scaffolds as simple structures, but they actually depend upon complex engineering and the balancing of different forces. That’s why the companies that design and build them invest so heavily in engineering – and why it’s so important to ensure that the people entrusted to oversee them on jobsites receive adequate training.
By respecting that complexity and ensuring that all employees involved with their erection and use are properly supervised, supervisors will be able to reduce the number of injuries and equipment damage caused by scaffold-related incidents.